I know that some beers are best when aged for a long time, and others, like wheats, are best when drank young. I was just wondering if there is a general rule of thumb for each style on when it is best to drink.

The general rule is the 1-2-3 method of 1 week in primary, two weeks in secondary, three weeks in bottles. However, most beers, especially high gravity beers, will be better served aging for a couple of months.

In general, the higher the gravity the longer it should age. The 1-2-3 method works well for most ale styles. Really big beers can take a much longer time; my wee heavy, for example, is bulk aging for 6 months, but that's an extreme example.